1. Technical Field
The present invention relates to cable connecting devices for connecting two different mechanisms of a vehicle seat via a cable for transmitting a mechanical operation amount from one to the other of the mechanisms such that the mechanisms are interlocked with each other. The two different mechanisms may be a mechanism disposed within a seatback of the vehicle seat and a mechanism disposed within a headrest positioned on an upper side of the seatback.
2. Description of the Related Art
WO20081026362 in the name of the same assignee as the present application discloses a cable connecting device including a cable serving as a mechanical operation amount transmitting device. The contents of WO2008/026362 are incorporated herein by reference. According to this publication, the cable includes a first cable routed within a seatback, and a second cable connected to the first cable in an axial direction and routed within a headrest. Each of the first and second cables has a double cable structure, in which a linear inner member is axially movably inserted into a tubular outer member. The second cable is routed within a tubular stay extending downwardly from the headrest, so that the stay serves as an outer member of the second cable. The stay is inserted into a tubular support disposed on the upper side of the seatback. A connecting end portion of the inner member of the first cable has an engaging projection that extends radially outward. Insertion slots are formed in the support and permit the engaging projection to extend therethrough and to move relative thereto in an axial direction. Receiving slots are formed in a connecting end portion of the stay and can receive the engaging projection of the inner member of the first cable in the axial direction. By inserting the connecting end portion of the first cable into the support from its lower side and engaging the engaging projection with terminal ends of the insertion slots formed in the support, the first cable can be brought to a state where the first cable is held to be suspended within the support. Then, the stay is inserted into the support from above and the outer member of the first cable is inserted into the stay, so that engaging projection engaging with the terminal ends of the insertion slots of the support is guided to move into the receiving slots formed in the stay. Therefore, with a head portion of the outer member of the first cable positioned proximal to the lower end of the inner member of the second cable, the inner member of the first cable and the stay engages to be connected to each other while they are permitted to move relative to each other in the axial direction by a distance.
Each of the insertion slots formed in the support has a configuration curved in one of opposite circumferential directions, while each of the receiving slots formed in the stay has a configuration curved in the other of the opposite circumferential directions. Therefore, as the engaging projection of the connecting end of the inner member of the first cable is guided to be moved from the position engaging with the terminal ends of the insertion slots formed in the support into the receiving slots of the stay, the inner member of the first cable rotates in the other direction in order to move the engaging projection from the terminal ends of the inserting slots to the terminal ends of the receiving slots. The headrest can be held at a mounted position by pressing the stay further downward relative to the support in the state where the first and second cables are connected to each other.
In the state where the engaging projection is engaged with the terminal ends of the insertion slots of the support and the first cable is held to be suspended within the support, the head portion of the outer member of the first cable is positioned within the support.
As described above, in order to connect the first and second cables to each other, the engaging projection of the first cable is first brought to engage with the insertion slots for suspending the first cable within the support. Then, the stay is inserted into the support, so that the engaging projection is disengaged from the insertion slots and is guided to move into the receiving slots for achieving connection between the first cable and the second cable. However, if the engaging projection is not in engagement with the terminal ends of the insertion slots even in the state where the first cable is suspended within the support, or if the insertion slots or the receiving slots are not formed at suitable positions, the engaging projection may not be guided to be smoothly move from the insertion slots to the receiving slots. In such a case, the engaging projection may be disengaged from the insertion slots before it moves into the receiving slots. Therefore, there is a possibility that the first cable falls off the support. Because the first cable is positioned within the seatback, it is not possible to visually recognize from the outer side as to whether or not the first cable has fallen off the support. In addition, because the first and second cables are connected to each other within the support that is embedded into the seatback, it is also not possible to visually recognize from the outer side as to whether or not the first and second cables are connected to each other.
Because the connecting condition between the first cable and the second cable cannot be visually recognized from the outer side, it has been assumed that the first cable and the second cable are connected to each other by the function of the connecting device in so far as the stay is inserted to be held within the headrest. Therefore, it has not been possible to reliably ensure the quality and the function of the vehicle seat. Thus, if the first cable and the second cable are not connected to each other, it is not possible to interlock between the mechanism disposed within the seatback and the mechanism disposed within the headrest via the cable.
Thus, there is a need in the art for a cable connecting device that enables to visually recognize from an outer side a connecting condition between a first cable and a second cable.